New process of textile fabrics dyeing

ABSTRACT

An anhydrous dyeing process comprising (a) achieving a fabric padding in a dyeing bath having a small capacity and containing at least one polar organic solvent chosen so that it dissolves the coloring agents used sufficiently at room temperature (solvent A); (b) defiling fabric in a closed enclosure filled with vapors of another solvent C, non-miscible with A, having a boiling point lower than solvent A and in which the coloring agents used are insoluble; (c) then sending the textile material into another closed enclosure, brought to the boiling temperature, of solvent C, in which solvent C is evaporated and recovered; (d) then, after cooling and quick rinsing in a convenient solvent to remove the non-fixed particles of coloring agents and residual quantities of solvent A, circulating the fabric in a last heated enclosure in order to remove and recover the rinsing solvent and finally winding the dyed fabric, ready for use.

United States Patent 1191 Hess et al.

[4 Aug. 21, 1973 NEW PROCESS OF TEXTILE FABRICS DYEING [73] Assignee: Soltex, Paris, France [22] Filed: July 28, 1970 [21] Appl. No.: 58,973

[30] Foreign Application Priority Data OTHER PUBLICATIONS White, W.A.S., American Dyestuff Reporter, July 31, 1967, pages (P591) 18 to (P597) 24.

Primary Examiner-Leon D. Rosdol Assistant Examiner-Harold Wolman Attorney-Browdy & Neimark [57] ABSTRACT An anhydrous dyeing process comprising (at) achieving a fabric padding in a dyeing bath having a small capacity and containing at least one polar organic solvent July 30, France chosen so that i dissolves h i g agents used Jan. 12, 1970 France 7001303 i y at room temperature (solvent fabric in a closed enclosure filled with vapors of an- [52] US. Cl. 8/85, 8/21 B, 8/54, other solvent C, nommiscible with A, having a boiling 8/l62 8/177 8,178 8/139 point lower than solvent A and in which the coloring Int. Cl 4 agents d are i l then sending the textile [58] Field at surch 8/93 material into another closed enclosure, brought to the 8/85 boiling temperature, of solvent C, in which solvent C is evaporated and recovered; (d) then, after cooling and [56] cued quick rinsing in a convenient solvent to remove the UNITED STATES PATENTS non-fixed particles of coloring agents and residual 3,667,898 6/1972 Bergman et al;.. 8/94 quantities of solvent A, circulating the fabric in a last 2,134,559 12/1939 Mellor et a1.. 81149.2 X heated enclosure in order to remove and recover the 3,512,913 5/1970 Day ct al 8/4 rinsing olvent and finally Winding the fabric, 3,524,718 3/1970 Nador et ai... 8/93 x ready f um 2,384,001 9/1945 Wesson 8/59 UK 1 1 3,617,211 11/1971 Dawson 8/173 10 Claims, 3 Drawing Figures 5 3T [3 TC p 0"0 Q 3.l I 8 2/ g 0 Patented Aug. 21, 1973 3 Sheets-Sheet l Patented Aug. 21, 1973 3 Sheets-$heet 2 000 O w O O (q 0 O J l O O O I Q 9W INVENTORB WILLY HESS &

J EAN-FRANCOIS GAMAURY ATTORNEYS Patented Aug. 21, 1973 3 Sheets-$heet 3 INVENTORS ATTORNEYS NEW PROCESS OF TEXTILE FABRICS DYEING The present invention relates to new techniques for the dyeing in anhydrous medium of textile materials having various forms such as fibers, yarns, wicks, cables, woven and non-woven fabrics, jerseys, having cellulosic fibers, or fibers with an anionic or basic character, or mixtures of those various types of fibers.

It has already been recommended to substitute solvents or mixtures of organic solvents wholly or partly for water traditionally used in textile dyeing operations. For this, numerous types of solvents and several dyeing methods, for example processes known as exhausting processes, have been described by specialists in this field.

Processes have been especially described according to which fibrous material is impregnated with a coloring agent dispersion or solution in an apolar organic solvent, and the support impregnated in this way is passed into an enclosure filled with vapors of the solvent (French Patent No. 1,444,332 filed June 4, 1965). However, this process is applicable only to a limited class of coloring agents having a lipophilic character when dissolved in the apolar solvent and is not commonly usable, especially for the dyeing of textile fibers having a basic character, as coloring agents of acid or metal-bearing acid types, the most commonly used in this case are practically insoluble in such a solvent and moreover have an hydrophilic charactenBesides, the use of such hydrophilic coloring agents is contemplated in the described process only in the dispersed or emulsified form which is not applicable to the coloring agents of acid or metal-bearing acid type. It is also essential according to the described operative method that the apolar solvent used for treatment in vapor state be the same or of the same type as the one used in the coloring agents dispersion or dissolution.

There has now been found a new method for the continuous dyeing of fabrics applicable in a general way to various types of fibers but especially advantageous for textile materials having fibers with a basic character which eliminates the above disadvantages and permits obtaining excellent results under optima conditions of temperature, coloring agents and dyeing bath quantities, and recovery of used anhydrous components.

In its most general form the process according to the invention, which is analyzed in the form of a combination of means, some of them being known while others are new by themselves, consists essentially of:

a. achieving a fabric padding in a dyeing bath having a small capacity and containing at least one polar organic solvent chosen so that it dissolves the coloring agents used sufficiently at room temperature (solvent b. defiling fabric in a closed enclosure filled with vapors of another solvent C, non-miscible with A, having a boiling point lower than solvent A and in which the coloring agents used are insoluble;

c. then sending the textile material into another closed enclosure, brought to the boiling temperature of solvent C in which solvent C is evaporated and recovered;

d. then, after cooling and quick rinsing in a convenient solvent to remove the non-fixed particles of coloring agents and residual quantities of solvent A, circulating the fabric in a last heated enclosure in order to remove and recover the rinsing solvent and finally winding the dyed fabric, ready for use.

According to an important variant in the field of the general process hereinabove, more especially applicable to textile materials having fibers with a basic character, it is possible to replace solvent A wholly or partially by a polar solvent A in which the coloring agents used are insufficiently soluble at room temperature but are soluble therein in the hot state and possibly add to it another solvent B, miscible in any proportion with solvent A or A, having a boiling point lower than solvent A or A and able to dissolve the coloring agents at any temperature. In this last case, the process has a further stage coming immediately after the padding phase which consists in passing the impregnated fabric into a closed enclosure having a temperature so that at the outlet, solvent B is removed, the vapors of this solvent being collected for recovery. The further phases used according to this variant are identical to that of the more general techniques described hereinabove. When using in the first stage only solvent A, recourse to solvent B is shown to be necessary in order that coloring agents be sufficiently dissolved; this measure is only optional when achieving padding in a mixture of the compounds A and A, which, moreover, must be miscible with each other. f

Solvent A is chosen mainly from aliphaticamides, especially non-substituted amides such as formamide, a non-toxic product easily available commercially. As a solvent A it is possible to use an aliphatic polyalcohol, as for example ethylene glycol. As solvent B an aliphatic monoalcohol such as methanol, ethanol, and isoprcpanol may be used. Solvent C is constituted preferably of an halogenated hydrocarbon such as trior perchlorethylene. It is also possible to use in each case mixtures of amides, mono-alcohols, polyalcohols and halogenated hydrocarbons. Moreover, according to the variant used, it is possible to use mixtures of monoand polyalcohols and/or of amides. As indicated above, solvents A and A and B are chosen in such a way that they are miscible in any proportion and their boiling points are sufficiently far from one another to allow a separated recovery. On the contrary solvents A, A and C must be non-miscible in order to avoid contamination of the solvent C liquid phase in the process third phase. Those solvents may, however, form azeotropes, as is the case for mixtures of perchlorethylene-ethylene glycol. Solvents B and C may be miscible or not, in any proportion and it matters little whether they may form an azeotrope, since solvent B must be wholly removed before the passing of the textile material through the solvent C vaporization enclosure.

In the first stage of the process according to the invention, fabric is contacted during a very short time, generally at room temperature, with a small quantity of dyeing bath, without having to take into account the ability of the dyeing agent to be absorbed by fibers, the concentration of such agents or, in the case of coloring agents mixture, the affinity differences for fibers that they may present between them in dyeing conditions. Indeed, the use of one or more of the precited A, A

and B solvents such as defined hereinabove and miscible between them in order to have in dyeing bath only one liquid homogeneous phase, avoids an ascent of coloring agents on the fibers of the fabric to be dyed when padding at room temperature, i.e. the dye is not fixed to the fibers in this stage. So, it is sufficient to feed to the padding tank only the quantity of coloring agent solution able to be carried physicallyby fabric without any other care except the maintenance of a sufficient level.

Moreover, when using the variant of utilization of solvent B, as when its boiling point is distinctly lower than that of solvent A and/or A, the sole passing of fabric through the first enclosure and removal therefrom at an outlet temperature such that all solvent B is removed (besides being able to be recovered by condensation of its vapors or otherwise) allows that the fabric be, during the third phase, only in the presence of solvent A and/or A, without solvent B.

According to the following phase of the process according to the invention, fabric goes through an enclosure filled with the vapors of solvent C. In such condition the fabric reaches a temperature at which coloring agents are in all cases quite soluble in solvent A and/or A and are absorbed by the fibers. The enclosure is preferably provided at its top with cooling tubes which condense solvent C and a heat source at the bottom of said enclosure intended for evaporating such solvent. So a condensation of solvent C takes place on fibers; at this stage, the properties of solvent C not to dissolve coloring agents and not to be miscible with solvent A and/or A are essential. Without this double property solvent C would carry coloring agent away during condensation, which would involve a decreasing in quantity of coloring agent and the risk of obtaining a bled dyeing. It is sometimes advantageous, in some cases, to add to solvent C an anhydrous organic compound, the vapors of which allow to improve coloring agent fixing as, for example, glacial acetic acid.

After passing into another heated enclosure, contiguous to the previous one and brought to the same temperature, in which are removed the last traces of solvent C carried away by the fabric, the fabric is cooled by passing it around a cool drum and is then introduced for quick rinsing in a pad containing an organic solvent mixcible with solvent A and/or A able to dissolve quickly in cold state and non-fixed coloring agent particles. There is used advantageously one of the organic compounds defined hereinabove as being usable as solvent B. After such rinsing this solvent, generally little soiled, is evaporated in a heat enclosure, joined to the rinsing pad and provided with a collecting device. In the case of the precited variant with use of solvent B, this device is preferably connected to the one of the first enclosure in order to collect together the totality of this solvent recovered in the whole of operation.

The process described hereinabove is very advantageously applicable to natural or synthetic fibers having a basic character such as polyamides and wool. But it may also be extended to other textile products which may be dyed, for example, to the materials having threads or fibers obtained from polymers containing more than 85 percent of acrylonitrile, of cellulose esters, as, for example, triacetate, natural (as cotton, flax) or regenerated (such as viscose rayon) cellulosic fibers, etc.

The range of coloring agents able to be used depends upon the nature of the material to be dyed and is extremely large. So, it is possible to quote, for example:

for basic fibers and fibers of cellulose esters: dyeing agents having an anionic character, which have one or several solubilizing groups such as sulfonic and carboxylic groups, preferably in free acid form and possibly complexed by a metal;

for anionic fibers: coloring agents having a cationic character, positively charged, for example, by the presence in their molecule ofa carbenium ion or of an atom of quaternary nitrogen;

for cellulosic fibers: anionic coloring agents generally called direct coloring agents.

The invention will be better understood in referring to the schematic drawings of FIGS. 1 to 3 which illustrate, in a non-limitative way, some devices which may be used for achieving the process according to the invention. Those devices are all described in conjunction with the variant including solvent B used, but they are easily adaptable to more general techniques in which solvent B is not used, only by suppressing the elements contemplated for this use.

On those figures 0 represents the initial roll of the fabric to be dyed. After passing into impregnation pad 1 containing the coloring agent(s) and solvent(s) A, A and B at room temperature, the fabric passes into the heated enclosure 2 from which solvent B vapors evolve, then into the enclosure 3 filled with solvent C vapors evolve, then into the enclosure 3 filled with solvent C vapors which are condensed by the cooling tubes 3.1 and reevaporated by the heated floor 3.2. The fabric is then passed through solvent C, vaporization enclosure 4, and then about a cooling roll 5 prior to passage to rinsing pad 6 (for example with 3 rolls) containing solvent B at room temperature, playing the part of the rinsing agent. After vaporization of rinsing solvent B in the enclosure 7 (vapors coming from enclosures 2 and 7 being collected after condensation and recycled) dyed fabric is wound on final mandrel 8. The device of FIG. 2 is substantially the same except for location of elements.

The device of FIG. 3 is more specifically intended for the dyeing of fibers other than the ones having a basic character and for the utilization of non-acid coloring agents. Indeed, in those cases, the time necessary for vaporization treatment, that is for textile contact with solvent C may be longer than in the other applications. So this increasing of vaporization times must normally need either the use of a longer enclosure 3, or a decreasing of speed of textile material travel in said enclosure. However, those disadvantages can be avoided in substituting for a part of textile course in enclosure 3 a winding thereof on a perforated mandrel 9. Dyeing operation takes place, in such conditions, In a semicontinuous way, roller 9 having, after a convenient residence time of textile in vaporization enclosure 3, to be unwound for traveling through devices 4, 5, 6 and 7.

The following examples show how the invention may be achieved. Except contrary indications, all parts are given by weight.

EXAMPLE l A continuous dyeing of a polyamide 6 linen of I00 g/m and cms wide was made by means of a coloring agent C.l. Acid blue No. 129 in free acid form and using as solvents:

A ethylene glycol B 2 ethanol C perchlorethylene After having passed the fabric in padding tank 1 with two rolls, filled with 30 l. of a mixture, at room temperature, of 500 parts by volume of ethylene glycol and 500 parts volume of a 20 g/l solution of the precited coloring agent in ethanol, the fabric was passed successively through enclosure 2 brought to 60C, this temperature being practically sufficient to evaporate all solvent B at the enclosure outlet (this because of the presence in said enclosure of an air stream), which is collected thereafter. Then the fabric passes in enclosure 3 filled with perchlorethylene vapors, then in chamber 4, both being maintained at 120C. After passing on cooling roller 5 maintained at about 20C by internal cold water circulation, rinsing was made in tank 6 with 3 rollers, of 72 1. capacity, filled with ethanol at room temperature, continuously renewed by overflow and circulation pump. Then the fabric was passed through enclosure 7 and there was recovered, at the end, on the roller 8 a polyamide fabric having a beautiful smooth shade of a quite bright blue. The analysis has shown no trace of ethylene glycol on the fabric.

The operation lasted on the whole three minutes from pad outlet 1 and the solvents B and C could be re covered and recycled practically such as they were for similar dyeing operations.

EXAMPLE 2 This example was operated under the same conditions and in the same device as in Example 1, achieving the dyeing in a continuous way of a twill 100 percent wool of 210 g/m in a width of 140 cms and using:

as a coloring agent: C.l. Acid blue 25 in acid form;

as solvents: ethylene glycol, ethanol and a mixture of perchlorethylene and acetic acid parts by weight of glacial acetic acid per 100 parts of perchlorethylene Dyeing bath containing a mixture, at room temperature, of 500 parts (volume) of ethylene glycol and 500 parts (volume) of ethanolcontaining 15 g/l of the precited coloring agent.

After a total time of 3 h minutes (2 2% minutes of which involved passage through enclosure 3), there was obtained a fabric having a bright mean blue color presenting excellent fastness. ln operating according to the traditional exhausting process with the same quantity of coloring agent used in aqueous medium, more than one hour would have been necessary for achieving dyeing operation.

EXAMPLE 3 This example was worked according to the same process as in Example 1, operating in a continuous way the dyeing of a fabric of natural silk of 85 glm 'in width of 120 cms. There was used:

as a coloring agent: C.l. Acid red 145 in free acid form;

as solvents: a mixture of ethylene glycol and glycerol (solvent A);

a mixture of methanol and ethanol (solvent B) perchlorethylene (solvent C) to which had been added 15 parts (per volume) of propionic acid per 1000 parts of perchlorethylene.

Dyeing bath contained, at room temperature, 1000 parts (volume) of the mixture of precited A and B solvents (at the rate of 250 parts of methanol per 250 parts of ethanol and 330 parts of ethylene glycol per 170 parts of glycerol) and I5 parts of coloring agent. After a dyeing time of only two minutes, there was obtained a fabric having a very bright orange color and not showing any bleeding during washings of the type ":1 according to the European mode of dyeing fastness.

EXAMPLE 4 In a mixture containing 5 parts of Light Solid Acid Black 2 BL in free acid form and parts of formamide (solvent A) a polyamide 6 fabric was padded. This fabric was circulated during two minutes in an enclosure filled with perchlorethylene vapor (solvent C) at 120C. Then the fabric was dried in an enclosure such that perchlorethylene and excess formamide were recovered. after cooling and rinsing with the help of propanol, followed with an isopropanol evaporation, there was obtained a full black shade, stable to rubbing, washing and light.

EXAMPLE 5 In the same way as in Example 4 a wool fabric was dyed by padding in a 50 g/kg formamide solution of Light Supracid Green BL in free acid form, then vaporization during two minutes in perchlorethylene vapors, drying and water rinsing.

EXAMPLE 6 By means of metal-bearing coloring agents, a military khaki shade, presenting all the fastness required for this kind of material, was obtained on polyamide 66 from a padding bath constituted by:

0.23 parts of Light lntracetyl Black RBLL 0.25 parts of Light lntracetyl Yellow 3 RLLL parts of formamide vaporization was achieved as in Example 5 in perchlorethylene vapors maintained at the boiling point, followedwith a drying and a rinsing.

EXAMPLE 1 media.

Light Lyrcamine Red 6 ELL 2 parts Light Lyrcamine Red RBLL 0.5 parts Light Lyrcamine Scarlet RL 2 parts EXAMPLE 8 In the same way as in Example 7, there is dyed a polyacrylonitrile jersey of ORLON type with the same padding baths, but substituting for perchlorethylene vapors, those of a mixture of perchlorethylene (48 percent) and trichlorethylene (52 percent) and leaving fabric stay about twenty minutes in this environment. In this case a winding device such as is described in Example l2 hereinafter is used.

EXAMPLE 9 A cotton fabric is impregnated with a bath constituted with 2 parts of Light Diazoll Blue R, 50 parts of formamide (solvent A) and 50 parts of methanol (solvent B). Then after having squeezed it between two rollers and having removed methanol, by drying at moderate temperature, fabric is vaporized during two minutes in perchlorethylene vapors (solvent C); then it is dried and rinsed with soapy water. A very bright blue shade is obtained in this way and has the usual fastness of direct coloring agents.

EXAMPLE 10 A fabric of cellulose triacetate is dyed by means of acid coloring agents in solution in formamide in the same way as in Example 9 using, in the vaporizing enclosure, vapors of a mixture of perchlorethylene (48 percent) and trichlorethylene (52 percent) such that the the boiling temperature is near lC. In such conditions padding bath being constituted with 2.5 percent by weight in formamide of Light Solid Acid Blue BRL in free acid form, there is obtained a good smooth and solid shade.

EXAMPLE ii A polyamide 6 jersey is padded in a bath containing two parts of Light Solid Acid Blue BRL in free acid form dissolved in a mixture of 25 parts of formamide (solvent A) and 50 parts of ethylene glycol (solvent A).

After squeezing the jersey passes during about two minutes in perchlorethylene vapor (solvent C). Then it is dried and rinsed in isobutyl alcohol. After drying there is obtained a solid, bright and blue shade.

EXAMPLE [2 A fabric of polyamide 6-6 is padded, according to the device represented by FIG. 3 in a bath containing two parts of Fuller Red RB in free acid form, dissolved in a mixture containing 25 parts of formamide (solvent A), 50 parts of ethylene glycol (solvent A) and 25 parts of methanol (solvent B). After impregnation followed with a passing in the first enclosure 2 in which methanol is evaporated, the fabric is wound on mandrel 9 in enclosure 3 in the presence of perchlorethylene vapors (solvent C). When all the fabric to be dyed has been wound in this way, it is then unwound and follows the same course as the one of the continuous device, that is, evaporation in enclosure 4, cooling on roller 5, rinsing in pad 6, then rinsing solvent evaporation in enclosure 7 before final winding on roller 8. There is obtained in this way a smooth, solid and red shade.

It will be obvious to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown in the drawings and describe in the specification.

What is claimed is:

l. A process for the continuous dyeing of textile materials in an anhydrous medium comprising:

a. passing textile material selected from the group consisting of wool, polyamide and polymer fibers containing more than 85 percent acrylonitrile through a dyeing bath of a first polar organic solvent containing dissolved therein a dyeing agent, said dyeing agent being soluble in said first organic solvent at room temperature or at an elevated temperature; and impregnating said textile material with said dye containing solvent, the dye being deposited but not fixed on the textile material;

b. passing said textile material through a heated enclosure filled with vapors of at least one halogenated hydrocarbon non-miscible with said polar organic solvent and having a boiling point lower than that of said polar organic solvent and in which said dyeing agent is insoluble, and effecting absorption of the dye by the textile and fixing of the dye aided by condensation of the halohydrocarbon on the textile material;

0. passing said textile material to a heated evaporation zone brought to the boiling temperature of said halogenated hydrocarbon and evaporating and recovering said halogenated hydrocarbon; and

d. cooling said textile and rinsing in an organic rinsing solvent, and evaporating and recovering said rinsing solvent.

2. A process according to claim 1 in which said first solvent comprises a polar solvent in which said dyeing agent is insufficiently soluble at room temperature but is soluble in hot state.

3. A process according to claim 2 wherein a second solvent miscible in any proportion with said first solvent with a boiling point lower than said first solvent and able to dissolve said dyeing agent at any temperature is used with said first solvent, said process having a further stage coming immediately after stage (a) and consisting of passing impregnated fabric in a shut enclosure, brought to such a temperature that, at outlet, said second solvent is removed, vapors of this solvent being collected for recovery.

4. A process according to claim 1 in which said first solvent is a non-substituted aliphatic amide.

5. A process according to claim 4 in which said amide is formamide and said halogenated hydrocarbon is perchloroethylene.

6. A process according to claim 2 in which said first solvent is an aliphatic polyalcohol or mixture of allphatic polyalcohols.

7. A process according to claim 6 in which said polyalcohol is ethylene glycol.

8. A process according to claim 3 in which said second solvent is an aliphatic monoalcohol or mixture of aliphatic monoalcohols.

9. A process according to claim 8 wherein said monoalcohol is methanol, ethanol, isopropanol or a mixture thereof.

10. A process according to claim 3 in which said organic rinsing solvent is the same solvent as said second solvent. 

2. A process according to claim 1 in which said first solvent comprises a polar solvent in which said dyeing agent is insufficiently soluble at room temperature but is soluble in hot state.
 3. A process according to claim 2 wherein a second solvent miscible in any proportion with said first solvent with a boiling point lower than said first solvent and able to dissolve said dyeing agent at any temperature is used with said first solvent, said process having a further stage coming immediately after stage (a) and consisting of passing impregnated fabric in a shut enclosure, brought to such a temperature that, at outlet, said second solvent is removed, vapors of this solvent being collected for recovery.
 4. A process according to claim 1 in which said first solvent is a non-substituted aliphatic amide.
 5. A process according to claim 4 in which said amide is formamide and said halogenated hydrocarbon is perchloroethylene.
 6. A process according to claim 2 in which said first solvent is an aliphatic polyalcohol or mixture of aliphatic polyalcohols.
 7. A process according to claim 6 in which said polyalcohol is ethylene glycol.
 8. A process according to claim 3 in which said second solvent is an aliphatic monoalcohol or mixture of aliphatic monoalcohols.
 9. A process according to claim 8 wherein said monoalcohol is methanol, ethanol, isopropanol or a mixture thereof.
 10. A process according to claim 3 in which said organic rinsing solvent is the same solvent as said second solvent. 